The present invention relates to an apparatus for changing direction of driving force for bicycles, more particularly, to an apparatus for changing direction of driving force for bicycles, which can travel bicycles forward by pedaling rearward as well as by pedaling forward. Also having simple structure and taking up small space, it can be installed on an outer portion of a pedal shaft, a rear wheel hub, more over, in the frame of bicycles.
In general, a bicycle can travel in only one direction, that is, travel forward by pedaling forward, thereby causing fatigue in a rider""s leg and uneven development in a leg muscle when the rider bicycles for a long time.
Thus, in order to solve the problems, many inventors have made an effort in the development of an apparatus for changing direction of driving force for bicycles which can be applied to a conventional one-directional pedaling bicycle.
The apparatus for changing direction of driving force for bicycles developed until now is classified into three fields roughly according to the methods adopted therefor, that is, methods using auxiliary gears, bevel gears and planetary gears.
As a representative invention related to the apparatus for changing direction of driving force for bicycles, Manrzoursos et al. (EPO Publication No. 0,369,925) disclose a system of bicycle motion transmission adopting auxiliary gears, Foster (U.S. Pat. No. 5,435,583) discloses a clutch operated, bi-directional, bicycle gear box adopting bevel gear and a clutch, and the invention of the same inventor of the present application(Korean Patent Application No. 98-1617) discloses an apparatus for changing power direction for bicycle adopting planetary gears.
However, because the above apparatuses are attached outside of the pedal shaft, the attached apparatus is protruding outside of a bicycle frame, thereby obstructing the pedaling of a rider. In addition, due to the protruding portion, it is difficult to attach the apparatus to a newly developed bicycle which can be folded for portability. Also the invention causes noise from engagement of ratchet gears which are indispensable for the inventions.
Thus, the above problems have raised requirements in development of a transmission for a bicycle, which can be attached to a shaft of a rear wheel and makes little noise, as an apparatus for changing direction of driving force for bicycles.
One of the example of such an apparatus for changing direction of driving force for bicycles, which can be installed on a shaft of a rear wheel, is Korean Patent Application 98-1616 of the inventor of the present invention.
Above invention discloses a driving direction changing apparatus of a bicycle hub, wherein a speed changing portion and a driving direction changing portion are installed, whereby it can transform the rearward pedaling to forward driving of bicycles and the speed of the bicycle.
However, the invention needs manipulation of a lever for transforming rearward pedaling to forward driving, more over, the invention can be installed only in the rear hub.
It is an object of the present invention to provide an apparatus for changing direction of driving force for bicycles, which can travel bicycles forward by pedaling rearward as well as by pedaling forward and can be installed on an outer portion of a pedal shaft, a rear wheel hub, more over, in the frame of bicycles.
Another object of the present invention is to provide an apparatus for changing direction of driving force for bicycles, which makes little noise, does not need to manipulate a lever in order to travel bicycles forward by pedaling rearward, and can be pulled back without a load like general bicycles.
According to the first aspect of the above object, there is provided an apparatus for changing direction of driving force for bicycles, the apparatus comprising: a pedal shaft having angular portion; a drive transferring portion composed of a carrier which is engaged with the angular portion, a forward clutch pin group and a reverse clutch pin group are formed therein, a first sun gear having inner surface which is driven by contacting with the forward clutch pin group and a gear portion is formed along outer circumference therein; a drive changing portion composed of a second sun gear which is driven by contacting with the reverse clutch pin group and a gear portion is formed along outer circumference therein, forward planetary gears which are engaged with the first sun gear, reverse planetary gears which are engaged with the forward planetary gears and the second sun gear at the same time; a sprocket which is formed along circumference of the extended portion of the first sun gear; a shaft housing having a plurality of pin holes; fixing means for fastening above elements.
According to the second aspect of the above object, there is provided an apparatus for changing direction of driving force for bicycles, the apparatus comprising: a pedal shaft having angular portion; a drive transferring portion composed of a carrier which is engaged with the angular portion, a forward clutch pin group and a reverse clutch pin group are formed therein, a connecting ring having inner surface which is driven by contacting with the forward clutch pin group; a drive changing portion composed of an inner gear which is driven by contacting with the reverse clutch pin group and a gear portion is formed along inner circumference therein, forward planetary gears which are engaged with the inner gear, reverse planetary gears which are engaged with the forward planetary gears and the ring gear through the connecting ring at the same time; a sprocket which is installed on the connecting ring; a shaft housing having a plurality of pin holes; fixing means for fastening above elements.
According to the third aspect of the above object, there is provided an apparatus for changing direction of driving force for bicycles, the apparatus comprising: a pedal shaft having angular portion; a drive transferring portion composed of a carrier which is engaged with the angular portion, a forward clutch pin group and a reverse clutch pin group are formed therein, a connecting ring having inner surface which is driven by contacting with the forward clutch pin group; a drive changing portion composed of a sun gear which is driven by contacting with the reverse clutch pin group and a gear portion is formed along outer circumference therein, planetary gears which are engaged with the sun gear, a ring gear which is engaged with the planetary gears and connected to the connecting ring through the connecting portion at the same time; a sprocket which is installed on the connecting ring; a shaft housing having a plurality of pin holes; fixing means for fastening above elements.
According to the fourth aspect of the above object, there is provided an apparatus for changing direction of driving force for bicycles, the apparatus comprising: a pedal shaft having angular portion; a drive transferring portion composed of a carrier which is engaged with the angular portion, a forward clutch pin group and a reverse clutch pin group are formed therein, a connecting gear having inner surface which is driven by contacting with the forward clutch pin group and a gear portion is formed therein; a drive changing portion composed of a first bevel gear which is driven by contacting with the reverse clutch pin group and a gear portion is formed therein, a second bevel gear which is engaged with the first bevel gear and gear potion of a connecting gear at the same time; a sprocket which is installed on the connecting gear; a shaft housing having a plurality of pin holes; fixing means for fastening above elements.